MOSCOW (Reuters) -- The Russian Orthodox Church has prayed for divine guidance in choosing a new leader, a process likely to pit conservatives against those who want to open up the church to the rest of the world.

The new patriarch will lead a church of about 165 million believers worldwide and determine whether to repair ties with the Roman Catholic Church that have been strained since a schism in 1054 split Christianity into eastern and western branches.

Several dozen of the church's most senior clergy, in gold-embroidered vestments, held prayers in Moscow's Cathedral of Christ the Savior in preparation for choosing a successor to Patriarch Aleksy II, who died last month.

"Today we raise our prayers so that this Council of Bishops restores the entirety of the Russian Orthodox Church by electing the new patriarch of Moscow and all Russia," said a senior clergyman at the service.

There has been no overt campaigning for the role but Russian media have showcased a vigorous debate between church-goers who favor sticking to tradition and modernizers who want to open up to the rest of the world.

Rival Camps

Religion scholars say the contest will focus around Metropolitan Kirill, 62, the church's top diplomat who has close ties with other faiths, and a conservative camp whose favored candidate could be 59-year-old Metropolitan Kliment.

Later on January 25, the Council of Bishops will gather in a hall in the Christ the Savior Cathedral -- rebuilt in the 1990s after the communist authorities blew up the original building -- to draw up a shortlist of at least three candidates.

Then a Local Council of about 700 priests, monks, and laypeople will convene on January 27 to choose the next patriarch. The final voting procedure has yet to be decided, but could involve a secret ballot or drawing lots at random.

The cathedral, a short distance from the Kremlin, was surrounded by hundreds of police. Orthodox activists gathered outside holding up ecclesiastical banners embroidered with the image of Jesus Christ.

"Let the Holy Spirit point to the most worthy candidate," read a placard held up by one believer.

Aleksy became patriarch in the dying days of the Soviet Union, whose policy of state atheism imposed restrictions on the activities of the church.

Since then, the Russian Orthodox Church has undergone a resurgence, with many Russians starting to embrace their religious heritage and hundreds of buildings confiscated by the communists returning to church use.

Vladimir Putin -- president for two terms before becoming prime minister last year -- has identified himself closely with the church and is frequently shown on television attending religious services.

Aleksy's critics said the late patriarch allowed the state to exploit its ties with the church for political gain and chose not to speak out about society's ills for fear of offending the church's backers in the Kremlin.